Sen. Susan Collins (R-Maine) said a crowdfunding campaign that has now collected millions of dollars in pledges to defeat her in 2020 is a “classic quid pro quo” and a violation of federal bribery laws.

“I think that if our politics has come to the point where people are trying to buy votes and buy positions, then we are in a very sad place,” Collins said Sunday on CBS’s “60 Minutes.”

A group of liberal activists began the campaign last month to pressure Collins, a key swing vote in now-Justice Brett M. Kavanaugh’s nomination, to vote against President Trump’s nominee. If Collins voted no, donations would not be taken from the donors. If she voted yes, the pledges would fund the campaign of the Maine Democrat who wins the nomination for the Senate seat in two years.

Collins’s office immediately called the campaign an attempt to extort her into making a decision.

“They are asking me to perform an official act and if I do not do what they want, [money] is going to go to my opponent,” she told “60 Minutes.”

Collins on Friday announced she would support Kavanaugh’s nomination amid decades-old allegations of sexual assault and concerns about threats to Roe v. Wade with predominantly conservative justices on the Supreme Court. Her support guaranteed a victory for Kavanaugh after a bruising confirmation battle.

After Collins’s announcement, pledges inundated the crowdfunding site Crowdpac, causing it to briefly crash.

By Monday morning, the campaign had surpassed $3.5 million in pledges from about 121,000 donors — not an insignificant amount for a political race in a state with one of the smallest populations in the country (1.3 million). The unusual fundraising effort by Maine People’s Alliance, Mainers for Accountable Leadership and activist Ady Barkan is a sign of an energized Democratic electorate and could set the stage for Collins’s reelection contest.

Sen. Chuck Grassley (R-Iowa), chair of the Senate Judiciary Committee, told Fox News he wants to help raise money to match the funds.

Marie Follayttar, co-director of Mainers for Accountable Leadership, denounced bribery accusations, saying attacking an effort by thousands of small-dollar donors is “politics at its worst.”

“Thousands of Mainers are trying desperately to tell her that she needs to protect abortion access and critical health care coverage across the country by voting ‘no’ on Kavanaugh,” Follayttar said in a statement last week, before Kavanaugh was confirmed. “If she doesn’t, we absolutely have the right to prepare to unseat her given everything Judge Kavanaugh would do on the Supreme Court to make life worse for Maine women, Mainers with preexisting conditions and Mainers who care about [the] fabric of our democracy. Unlike Supreme Court judges, Senators do not enjoy a lifetime guarantee of their seat; they are accountable to the people.”

One ethics expert told The Washington Post that the crowdfunding campaign may very well violate federal bribery statutes, which prohibit giving or offering anything of value to government officials in exchange for any acts or votes.

As the pledges poured in, yet another unusual series of events in these hyperpartisan times unfolded on social media: the online crowdsourcing for a nominee and that nominee’s future campaign staff.

“Who wants to run for Senate in Maine? There will be an army of supporters with you,” tweeted Jen Psaki, White House communications director under President Barack Obama.

“Me,” Susan E. Rice, Obama’s former United Nations ambassador and national security adviser, replied, raising a flurry of questions about what her plans are.

Rice, whose family is from Portland, Maine, later clarified, saying she’s not making any announcements. But on Sunday, she kept the possibility of running open, saying she will decide after the November elections whether to launch a bid to unseat Collins. Speaking at the New Yorker Festival in New York, Rice said Collins “put party and politics over her own stated principles” of supporting equal rights and legalized abortion.

Jenna Lowenstein, a Democratic digital strategist who worked on Hillary Clinton’s presidential campaign, also said she had enlisted 75 political staff members to help elect Collins’s future challenger. In a Google docs sign-up sheet she created, Lowenstein promised to send volunteers to the campaign as soon as there is one.

“Nothing like starting with binders full of women (and men) ready to take up the fight,” she wrote.

The Senate on Saturday confirmed Kavanaugh in a largely partisan 50-to-48 vote, cementing a conservative majority on the nation’s highest court. Hundreds of protesters — many chanting, “We believe survivors!” “Vote them out!” and “Shame, shame, shame” — converged on the U.S. Capitol as the Senate prepared to vote.

Kavanaugh’s confirmation was all but certain after Collins, Jeff Flake (R-Ariz.) and Joe Manchin III (D-W.Va.) said they would vote to confirm the judge. One Republican, Sen. Lisa Murkowski (Alaska), broke with her party.

Collins had initially expressed concern about threats to Roe v. Wade if Kavanaugh were confirmed, effectively shifting the Supreme Court to the right for decades. The senator also had been among the holdout votes amid an FBI investigation of sexual assault allegations against Kavanaugh, whose nomination seemed in peril three weeks ago.